Saturday is the last day that Californians can sign up for Obamacare coverage and have their new policies start on April 1, a deadline that is extra important for anyone with a COBRA health-insurance policy.

An official for the state’s health exchange confirmed Friday that failing to sign up by midnight Saturday could result in COBRA members having to pay an extra month’s premium or suffer a gap in insurance coverage.

COBRA stands for the Consolidated Omnibus Budget Reconciliation Act of 1985, a piece of legislation that allows individuals who lose or leave their job to continue on their former employer’s insurance as long as they pay the full cost of that coverage, including any portion their former company paid when they were still on the payroll.

Covered California plans, because they offer income-based premium subsidies, can be much more affordable, especially for those who have lost a job and seen their income plummet.

Bruce Elliott, manager of compensation and benefits for the Society for Human Resource Management, said for most people who have lost their jobs, dropping COBRA and getting an exchange-based plan is much cheaper because the Affordable Care Act grants significant subsidies based on income. The recently unemployed, he noted, will generally have little problem making the case that their income is low enough to qualify for a subsidy.

“In nine out of 10 cases, getting an exchange plan is going to be way cheaper,” Elliott said.

He added that COBRA plans run month to month, so it’s possible to cancel them relatively quickly.

That’s good because the Affordable Care Act, which requires most Americans to buy health insurance if they don’t already get it from their employer or a government program like Medicare, allows enrollment in exchange plans only if the applicant has no other qualifying coverage in place.

Roy Kennedy, a spokesman for Covered California, said anyone applying for coverage must make sure their COBRA coverage has lapsed before their new Covered California plan starts.

“You can have one or the other, but not both at the same time,” Kennedy said.

This snake dance is complicated by the fact that the six-month open enrollment period for health exchanges nationwide will end on March 31. Anyone who applies by midnight Saturday and pays their first month’s premium by March 26 will have their policy start on April 1. Applications submitted after the 15th would result in the policy taking effect on May 1.

Because COBRA insurance runs in one-month periods and the start of Covered California coverage can be delayed for up to six weeks depending on when an applicant signs up, making the transition from COBRA to health exchange can result in a coverage gap or in an extra monthly COBRA premium.

Consider this hypothetical situation: A local resident with a $1,500 monthly COBRA policy that runs out on March 25, signs up for a Covered California plan on March 16. Because his enrollment date is after the 15th of the month, his coverage would not begin until May 1. That would leave a monthlong gap in coverage or would require another $1,500 for the April COBRA payment.